Re: [Qemu-devel] [PATCH v2 40/67] target/arm: Implement SVE Integer Compare - Scalars Group

[Richard Henderson]

On 02/23/2018 09:00 AM, Peter Maydell wrote:
>> +
>> +uint32_t HELPER(sve_while)(void *vd, uint32_t count, uint32_t pred_desc)
> 
> This could really use a comment about what part of the overall
> instruction it's doing.

Ok.

>> +
>> +    /* For the helper, compress the different conditions into a computation
>> +     * of how many iterations for which the condition is true.
>> +     *
>> +     * This is slightly complicated by 0 <= UINT64_MAX, which is nominally
>> +     * 2**64 iterations, overflowing to 0.  Of course, predicate registers
>> +     * aren't that large, so any value >= predicate size is sufficient.
>> +     */
...

> I got confused by this -- it is too far different from what the
> pseudocode is doing. Could we have more explanatory comments, please?

Ok.  I guess the comment above wasn't as helpful as I imagined.  I'll come up
with something for the next round.


r~